JP2023085905A - Method for creating three-dimensional geological model of tunnel - Google Patents

Abstract

To provide a method for creating a three-dimensional geological model of a tunnel, which enables intuitive understanding of an actual geological structure by connecting geological images of an inner peripheral surface appearing after excavation of the tunnel.SOLUTION: The present invention is a method for creating a three-dimensional geological model of a tunnel whose excavated surface and inner peripheral surface are covered with shot concrete. It comprises steps (S1-S3) of repeating the work of acquiring image data of parallax image and RGB image by photographing the excavated surface including the shot part of the shot concrete after excavation for each unit excavation process, a step S4 of creating a unit three-dimensional model from the image data for each unit excavation process, a step S5 of creating an initial synthetic model by superimposing overlapping portions of unit three-dimensional models of successive unit excavation processes, and a step S6 of creating a three-dimensional geological model by removing the shot part from the initial synthetic model.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for creating a three-dimensional geological model of a tunnel whose excavated surface and inner peripheral surface are covered with shotcrete.

Observation of the face immediately after excavation to understand the geological structure around the tunnel is essential for process control, safety control, and quality control of mountain tunnel construction. For this reason, the construction staff observes the face (the front of the tunnel at the tip of the excavation) at each excavation and records the geological information of the face (rock type, cracks, hardness, etc.).

Here, since there is a danger of falling rocks and collapses directly under the face, shotcrete should be applied immediately after excavation, and the next process should be carried out after ensuring the safety of the area directly under the face. Direct observation of the surrounding geological information is possible only for a short time after excavation.

Currently, photographs of the face are recorded for each excavation, but since the geological information is for each excavation (about 1m), the information is intermittent, making it difficult to understand the geological structure of the entire tunnel continuously at a glance. is difficult.

On the other hand, as disclosed in Patent Documents 1 to 3, various methods for measuring the accurate shape of the face and devices for photographing excavated surfaces such as uncut tunnel side walls have been developed. .

Japanese Unexamined Patent Application Publication No. 2016-200521 Japanese Patent Application Laid-Open No. 2018-109311 Japanese Unexamined Patent Application Publication No. 2018-204288

However, as mentioned above, most of the inner surface of the tunnel is covered with shotcrete immediately after excavation in order to ensure safety. Limited to a small part near the face. It is difficult for an inexperienced engineer to correctly understand abrupt geological changes such as faults just by collecting these partial photographs.

Therefore, the present invention provides a method for creating a three-dimensional geological model of a tunnel that enables intuitive understanding of the actual geological structure by connecting geological images of the inner peripheral surface that appear after excavation of the tunnel. intended to provide.

In order to achieve the above object, a method for creating a three-dimensional geological model of a tunnel according to the present invention is a method for creating a three-dimensional geological model of a tunnel in which the excavated surface and the inner peripheral surface are covered with shotcrete. a step of repeating for each unit excavation process an operation of acquiring image data of a parallax image and an RGB image by photographing an excavation surface including the sprayed portion of the shotcrete; , creating a unit three-dimensional model respectively; creating an initial synthetic model by superimposing overlapping portions of the unit three-dimensional models of the continuous unit excavation process; and from the initial synthetic model to the spraying section and creating a three-dimensional geological model by removing

Here, the operation of acquiring the image data is performed by a photographing device that is self-propelled to the vicinity of the face of the tunnel immediately after excavation, and the photographing device is configured to photograph the inner peripheral surface of the tunnel in the circumferential direction. can be

Further, the parallax image may be acquired by photographing with a stereo camera, and the RGB image may be acquired by a high-resolution camera. Further, the unit three-dimensional model is created by superimposing the point cloud data generated from the parallax image and the RGB image, and superimposition of overlapping portions when creating the initial synthetic model is performed by the point cloud data. The configuration can be performed on the basis of group data.

In the method for creating a three-dimensional geological model of a tunnel according to the present invention configured as described above, image data of parallax images and RGB images are acquired by photographing the excavation surface including the sprayed portion. Then, the three-dimensional geological model is created by removing the sprayed portion from the initial synthesized model in which the unit three-dimensional models created from the image data are superimposed.

Therefore, the geology of the inner peripheral surface that appears after the excavation of the tunnel can be continuously connected, and even an inexperienced engineer can intuitively understand the actual geological structure.

4 is a flow chart for explaining the flow of processing of a method for creating a three-dimensional geological model of a tunnel according to the present embodiment; It is explanatory drawing which showed the outline|summary of the imaging|photography situation by a self-propelled imaging device. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the camera unit of a self-propelled imaging device, (a) is an external view, (b) is explanatory drawing inside which removed the protective case. 1 is an explanatory diagram showing an outline of the principle of a stereo camera; FIG. FIG. 4 is an explanatory diagram illustrating parallax images obtained by photographing with a stereo camera; FIG. 4 is an explanatory diagram illustrating processing of point cloud data; FIG. 4 is an explanatory diagram showing an overview of processing for creating a unit three-dimensional model from parallax images and RGB images; FIG. 11 is an explanatory diagram showing an outline of a process of superimposing unit three-dimensional models that are continuous in the excavation direction; It is explanatory drawing which illustrated the three-dimensional geological model.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a flow chart for explaining the flow of processing of a method for creating a three-dimensional geological model of a tunnel according to this embodiment. FIG. 2 is an explanatory diagram showing an outline of a photographing situation by the self-propelled photographing device 1 as the photographing device.

In the construction of a tunnel T such as a mountain tunnel, the natural ground is excavated by an excavator, and the exposed excavated surface is promptly covered with shotcrete. FIG. 2 shows a state in which an excavator (not shown) has retreated in the direction of the tunnel mouth, and shotcrete has been applied to provide a sprayed portion F1.

The excavation of the tunnel T is performed by excavating a face T1 at the forefront of the excavation indicated by a semicircle in FIG. Behind the face T1 (pit side), the inner peripheral surface of the tunnel T formed in a semi-cylindrical shape appears.

Immediately after excavation, the inner peripheral surface of the tunnel T is exposed as the excavated peripheral surface T2. Replaced by F1.

For example, in a construction where about 1 m is a unit excavation process, every time the face T1 is excavated by 1 m, the uncut peripheral surface T2 for 1 m is extended, and the sprayed portion F1 is newly formed on the inner peripheral surface for 1 m behind it. will be set in In addition, the spray part F1 can also be collectively provided for several processes.

In the method for creating a three-dimensional geological model of a tunnel according to the present embodiment, the uncut peripheral surface T2 and the sprayed portion F1 are photographed together. On the inner peripheral surface of the tunnel T between, the uncut peripheral surface T2 is always exposed.

The excavated surface can be photographed by, for example, a self-propelled photographing device 1 as shown in FIG. This self-propelled photographing device 1 is a device for safely photographing the inner peripheral surface of the tunnel T near the face T1 by remote control.

The self-propelled photographing device 1 includes a traveling section 11 serving as traveling means, an arm section 12 extending upward from the traveling section 11, and a camera unit 2 attached to the tip of the arm section 12. there is The running part 11 is preferably provided in a crawler type so that it can run even on the uneven ground T3.

Although not shown, the self-propelled photographing apparatus 1 includes a receiving unit for receiving operation signals, a control unit for operating the driving unit according to the operation signals, and a calculation unit for causing the camera unit 2 to perform photographing and recording. It also has a processing unit, a storage unit, a battery, and so on. Furthermore, it is possible to install an inertial measurement unit (IMU) that measures angular velocity and acceleration with high precision for control of automatic driving.

FIG. 3 is a diagram illustrating the camera unit 2 of the self-propelled photographing device 1. As shown in FIG. 3(a) shows an external view, and FIG. 3(b) shows the inside of the camera unit 2. As shown in FIG. The camera unit 2 is covered with a rectangular parallelepiped protective case 21 .

When the protective case 21 is removed, a stereo camera 22, a high-resolution camera 23, and a line laser 24 are incorporated as shown in FIG. 3(b). The protection case 21 is provided with a window made of a transparent plate or the like for protecting the stereo camera 22, the high resolution camera 23 and the line laser 24. As shown in FIG.

FIG. 4 is an explanatory diagram showing an overview of the principle of the stereo camera 22. As shown in FIG. The stereo camera 22 incorporates a pair of cameras separated by a distance B between the cameras. The left camera captures the left image, and the right camera captures the right image.

When _the object P is photographed _{by the} stereo camera ₂₂ , _{the object} P is filmed. Then, the lens distance of the left and right cameras (inter-camera distance B), the focal length f of the left and right cameras, and the coordinate positions of the object P on the left and right images (P _L (x _L , y _L ), P _R (x _R , y _R )), the three-dimensional coordinates (X, Y, Z) of the object P can be calculated. In a situation where it is difficult to photograph the object P, it is possible to visualize the object P to be specified on the left and right images by illuminating the laser output from the line laser 24 .

FIG. 5 is an explanatory diagram exemplifying a parallax image obtained by photographing with the stereo camera 22. As shown in FIG. In short, a parallax image indicating the distance from the stereo camera 22 can be created from the left image and right image captured by the stereo camera 22 .

For example, when the inner peripheral surface of the tunnel T, such as an excavation surface, has unevenness, by extracting only the range in which the distance from the stereo camera 22 is shorter than a predetermined value, only the convex portions of the inner peripheral surface can be detected. It can be output as group data.

Next, the flow of processing of the method for creating a three-dimensional geological model of a tunnel according to this embodiment will be described with reference to the flowchart shown in FIG.
First, at the construction site of the tunnel T, excavation work is performed for each unit excavation process (step S1). For example, after a 1 m excavation is performed by blasting or an excavator, the excavated soil is carried out, and the inner peripheral surface of the tunnel T exposed in the previous unit excavation step is covered with shotcrete.

Subsequently, the self-propelled photographing device 1 is caused to travel toward the face T1 immediately after excavation. At this stage, the excavator, excavated earth and sand, spraying work vehicle, etc. have retreated to the tunnel mouth side, and there is no object in the vicinity of the face T1 that will interfere with photographing.

The self-propelled photographing device 1 is moved to a position suitable for photographing in the vicinity of the face T1 by remote control. When the self-propelled photographing device 1 is under automatic operation control, the self-propelled photographing device 1 travels by itself on the ground T3 to the position of the set coordinates.

For example, as shown in FIG. 2, the self-propelled photographing device 1 stops on the axis of the tunnel T in front of the uncut peripheral surface T2, which is the inner peripheral surface of the tunnel T newly exposed in the current process. Let The self-propelled photographing device 1 can photograph by operating the camera unit 2 at the tip of the arm portion 12 in the circumferential direction R.

Therefore, the lens of the camera unit 2 is directed to the leg of the arch-shaped excavation peripheral surface T2, and the camera unit 2 is rotated in the circumferential direction R from there to the top end of the tunnel T and the leg on the opposite side. Then, continuous shooting is performed (step S2).

The photographing area 20 is set so as to include, in terms of width in the excavation direction of the tunnel T, the newly exposed 1m-long uncut circumferential surface T2 and the 2m-long sprayed portion F1 adjacent to it. be done. Note that the photographing area 20 may include areas other than the 3 m width described above, the ground T3, the face T1, and the like. Unnecessary images may be removed in a process described later.

In photographing by the camera unit 2, photographing by the stereo camera 22 and photographing by the high resolution camera 23 are performed simultaneously. Further, when photographing a place with few features such as a flat surface, it is possible to photograph while irradiating the line laser 24 as auxiliary light.

At the time of photographing, the photographing date and time are also recorded together with the image. Further, when the self-propelled photographing device 1 has position information, the position information is also recorded together with the image. For example, when the self-propelled camera 1 equipped with an inertial measurement unit (IMU) is run, the angular velocity and acceleration detected during the run are integrated, so the position information of the position where the camera is stopped after running from the position of known coordinates. is obtained.

Up to this point, the unit excavation process and the photographing process are one process, after which the tunnel construction is restarted (step S31). Then, in step S32, it is determined whether or not to continue photographing.If photographing is to be continued, follow "YES" and proceed to step S1. On the other hand, if the photographing is finished and the three-dimensional geological model is to be created, the process proceeds to step S4 (NO in step S32).

As described above, the image data of the parallax image can be obtained from the images captured by the stereo camera 22 . Further, image data of an RGB image can be acquired from the image captured by the high-resolution camera 23 .

FIG. 6 is an explanatory diagram illustrating the processing of point cloud data obtained from parallax images. In the parallax image, distance data from the stereo camera 22 can be obtained, so point cloud data can be generated by extracting convex portions closer to the stereo camera 22 than the threshold as points.

The upper diagram in FIG. 6 illustrates point cloud data generated from a parallax image including a 1 m long uncut peripheral surface T2 and a 2 m long sprayed portion F1. Image data of the excavation peripheral surface T2 is the most important for creating a three-dimensional geological model.

On the other hand, the ground T3, the unexcavated face T1, and the point cloud data of redundant portions not used for superimposition can be removed at this stage. The point cloud data and the image data of the RGB image thus obtained are developed on a plane for subsequent superimposition processing.

FIG. 7 is an explanatory diagram showing an overview of the process (step S4) for creating a unit three-dimensional model from parallax images and RGB images.
From the point cloud data obtained from the parallax image and the image data of the RGB image, a range of 3 m width at the same position (process range for one shooting) is extracted.

Therefore, the unit three-dimensional model is created by superimposing the point cloud data developed on the plane and the image data of the RGB image, and restoring the three-dimensional shape of the inner peripheral surface of the tunnel T again. This unit three-dimensional model includes a 1 m long uncut peripheral surface T2 (rock) and a 2 m long sprayed portion F1 (concrete).

Such a unit three-dimensional model is created in units of imaging times. Then, in step S5, a three-dimensional initial composite model is created by superimposing a plurality of unit three-dimensional models that are continuous in the tunnel T excavation direction.

FIG. 8 is an explanatory diagram showing an outline of the process of superimposing three unit three-dimensional models that are continuous in the excavation direction. Here, since the uncut peripheral surface T2 existing in the unit three-dimensional model of each time will be covered with shotcrete and hidden in the next imaging time, it cannot be used as a reference for superimposition.

Therefore, superposition is performed using the spraying part F1. That is, the sprayed portion F1 of 1 m adjacent to the uncut peripheral surface T2 photographed for the first time also exists in the unit three-dimensional model created by the photographing for the second time.

Therefore, by superimposing the overlapping parts of the first unit 3D model and the second unit 3D model that model the same part, the first unit 3D model and the second unit 3D model are connected. match.

The point cloud data of the sprayed portion F1 is used when superimposing the overlapping portions. That is, the point cloud data of the second unit three-dimensional model that match the features of the point cloud data of the first unit three-dimensional model are extracted, and they are specified as the same portion and superimposed.

The same location can be specified not only by the convex portion of the blowing portion F1, but also by the positions of the shoring and rock bolts. Further, an image segmentation technique can be applied to identify the uncut peripheral surface T2 and the sprayed portion F1.

Then, when superimposing the unit three-dimensional models for the third time, the same process as for the first and second superimpositions is performed. That is, the unit three-dimensional model of the third time is superimposed on the three-dimensional model obtained by synthesizing the first and second times.

The initial composite model created in this manner is a three-dimensional model having three times (3 m) of the uncut peripheral surface T2 and the third 1 m of the sprayed portion F1. Therefore, in step S6, a three-dimensional geological model is created by removing the sprayed portion F1 of 1 m from the initial synthesized model (see the bottom diagram of FIG. 8).

FIG. 9 is an explanatory diagram illustrating a three-dimensional geological model created by the method of creating a three-dimensional geological model of a tunnel according to the present embodiment. That is, by connecting unit three-dimensional models created for each photographing time in the excavation direction, a three-dimensional geological model from the start of excavation of the tunnel T to the present can be created.

Next, the operation of the method for creating a three-dimensional geological model of a tunnel according to this embodiment will be described.
In the method for creating a three-dimensional geological model of a tunnel according to the present embodiment configured as described above, by photographing an excavation surface such as the uncut peripheral surface T2 including the sprayed portion F1, parallax images and RGB images are obtained. Get data.

Then, a three-dimensional geological model of only the excavated surface is obtained by removing the part corresponding to the superfluous sprayed part F1 from the initial synthesized model in which the unit three-dimensional models created from the image data are superimposed in the excavation direction. create.

In this way, it is possible to continuously connect the geological information of the inner surface that appears after excavation of the tunnel, so that even inexperienced engineers can intuitively understand the actual geological structure. Become.

In other words, it will be possible to confirm geological information such as rock types, cracks, hardness, etc., which are important for process management, safety management, and quality control of mountain tunnel construction, with a three-dimensional visualization of the geological structure. changes in

Further, if the self-propelled photographing device 1 that is self-propelled to the vicinity of the face T1 of the tunnel T immediately after excavation is used for photographing, it is not necessary for a person to approach and observe the face T1, which is in danger of falling rocks or collapsing. Also, it becomes possible to observe the uncut surface immediately after excavation, and it is possible to perform highly accurate rock ground evaluation from cracks and the like.

Furthermore, by creating a three-dimensional geological model of the bedrock surface, it becomes possible to observe the rock mass at any time later. In addition, since the three-dimensional geological model can grasp the unevenness of the excavation surface, it can be used for fault and key block analysis.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment. Included in the invention.

For example, in the above-described embodiment, the camera unit 2 including the high-resolution camera 23 was described as an example, but the present invention is not limited to this, as long as a digital camera capable of acquiring image data of RGB images is provided. .

In the above embodiment, the unit excavation process is 1 m in the excavation direction, but the unit excavation process is not limited to this. can be set to

1: Self-propelled imaging device (imaging device)
11: Traveling unit 22: Stereo camera 23: High resolution camera T: Tunnel T1: Face T2: Uncut peripheral surface (inner peripheral surface, excavated surface)
F1: Blowing part R: Circumferential direction

Claims (4)

A method for creating a three-dimensional geological model of a tunnel in which the excavated surface and the inner peripheral surface are covered with shotcrete,
a step of repeating, for each unit excavation step, an operation of acquiring image data of a parallax image and an RGB image by photographing an excavation surface including the sprayed portion of the shotcrete after excavation;
creating a unit three-dimensional model from the image data for each unit excavation process;
creating an initial composite model by superimposing overlapping portions of the unit three-dimensional models of successive unit excavation steps;
creating a three-dimensional geological model of a tunnel by removing the sprayed portion from the initial synthetic model. The work of acquiring the image data is performed by a photographing device that is self-propelled to the vicinity of the face of the tunnel immediately after excavation, and the photographing device is characterized in that it photographs the inner peripheral surface of the tunnel in the circumferential direction. The method for creating a three-dimensional geological model of a tunnel according to claim 1. 3. The method of creating a three-dimensional geological model of a tunnel according to claim 1, wherein the parallax images are acquired by photographing with a stereo camera, and the RGB images are acquired by a high-resolution camera. The unit three-dimensional model is created by superimposing point cloud data generated from the parallax image and the RGB image,
4. The three-dimensional geological model of a tunnel according to any one of claims 1 to 3, wherein overlapping parts are superimposed when creating the initial synthesized model based on the point cloud data. How to create.

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